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Colchester Master Original Headstock Adjustment

jinxie

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#1
hello all,
I am new to this forum but have used several similar forums in the past dealing with motorbikes, cars and also engineering interests. I have asked this question at previous forums but not had a definitive reply and thought this may be a more appropriate group to try again.
Whilst levelling my lathe I found that there was a .001" movement in the vertical axis when using a little leverage on the test bar. There is a similar amount of end play when levering between the chuck and the Headstock. I think this has been the cause of the problems I have had particularly when parting off and forming large chamfers or using form tools.
It would appear that there is a means of removing this play but I cannot find the method of doing this. The only manual I have been able to obtain shows only the Headstock detail for the later model Masters but not the Original. I am hoping someone may have a similar machine and may be able to offer some advise on the adjustment method. I have some photos of a similar Headstock which may help in this regard and when I find out how to post them I will do so.

Thanks in advance.

Jinxie
 

Bob Korves

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#2
Using a lever can show you flex in the various parts or looseness in the chuck mounting or the spindle bearings. Is it clear that you are measuring play (looseness) vs. flexing? If it is flex you must live with it or get a different lathe. If it is looseness, what type(s) of bearings are used for the spindle? What type of chuck mounting does the lathe use?
 

jinxie

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#3
Hi Bob, thanks for your comments.
Chuck is a screw on fit with a very positive register accurate within a few 10ths so very confident of the fitment. I don't know the type of bearings because there is no real info on this lathe. All I can find is the makers promotional info which doesn't help at all. Tony at Lathes.co.uk has no more info than this either, surprisingly. There is a collar in front of, and behind, the headstock with holes for adjustment by C spanner. The same arrangement is provided at the gearing end of the headstock so adjustment seems possible. What I need to know is the method of adjustment. I am not surprised there is wear all over the machine, it is after all 70 odd years old. I can live with wear but if it is possible to improve something I am all for trying to do so. I need to add photos but haven't figured it out yet.

Thanks again.

Jinxie
 

dlane

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#4
You should be able to add a couple pics , if useing tapatalk it's different here, search using tapatalk When replying as I am now And the pics are on your computer hit upload a file
(Lower right center) It should take you to your photo library where you can select the pics to upload, at least on apples it dose.
Where is Coulonges ?
 

Bob Korves

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#6
From the photos it appears to have roller bearings for the spindle. The nut on the left end of the spindle with the spanner wrench holes in it is where the adjustment is made. There may be a set screw or other locking mechanism that needs to be loosened first. Tighten the adjuster nut until the play goes away (use an indicator) and there is a VERY SLIGHT drag with turning the spindle with all the gearing in neutral, just the spindle turning. The adjustment nut will likely require only a small fraction of a revolution to get the play out. Check to see that the play is gone. Then run the lathe, starting at low speeds, for half an hour or so, speeding it up at intervals, and feeling the bearing areas for too much heat. The bearings should get warm but not too hot to touch. Maybe 100 degrees F. If hot the bearings are too tight, loosen the preload a bit and test again. These instructions are common to many lathes with roller bearings, but not yours in particular. Use at your own risk... (!)

Hmmm, spanner holes at both ends... The bearings may be adjusted separately(?) The bearings closest to the chuck would be preloaded, the one by the change gearing just enough to get the play out.
 
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